The present application relates generally to an improved data processing apparatus and method and more specifically to mechanisms for utilizing multiple memory pools during mobility operations to enhance performance and better utilize system resources.
Live Partition Mobility (LPM) is a feature of POWER6® and POWER7® servers that allows a running logical partition (LPAR) to be relocated from one system to another. POWER6 and POWER7 are trademarks of International Business Machines Corporation in the United States and other countries. The source and target systems must have access to the same network and storage area networks (SANs) but need not be of the same type. Partitions that are to be relocated must be fully virtualized (i.e., have no dedicated input/output (I/O) adapters) although it is possible to use multi-pathing software to fail over to virtual adapters for the duration of the move.
Any sized partition can be moved; essentially, memory is copied asynchronously from one system to another to create a clone of a running partition, with “dirty” pages being re-copied as necessary. When a threshold is reached (i.e., when a high percentage of the pages have been successfully copied across), the partition is transitioned to the target machine and any remaining pages are copied across synchronously. The agents that carry out the memory copying are nominated Virtual I/O Servers (VIOS) on each machine. LPM is used to avoid outages for planned server maintenance, for load balancing across multiple servers and for energy conservation.